Submitted by BillB on 7/26/2011

DIY Bathroom Remodel

Days 9-16 - Build Shower

Contents

• Project Blog
• Day 9 - Framing - Add Blocking
• Day 10 - Cement Board
• Day 11 - Curb, Kerdi Drain
• Day 12 - Mud Pan
• Day 16 - HydroBan

Day 9 - Framing - Add Blocking 

Our old shower tile walls had horozontal cracks along each wall, beneath which, I guessed, were the CBU edges. The cracks were parallel and 3 feet apart, so it was pretty obvious, as a sheet of CBU is 3 feet wide. When I demoed the shower I verified that the builder neglected to install any blocking where the CBU edges would be nor did he tape and thinset the edges! No wonder it cracked.

So here's my blocking, placed where the CBU edges will be. I interpreted the CBU installation instructions to say to drive a screw every 8", including around the perimeter; the ony way to achieve that is to install backing. But I think I was wrong based on forums I've read. You meet the manufacturer's specs by placing fasteners every 8" on the studs and the studs need to be at most 16" apart. Still, I'd add blocking anyway. DIY is all about overkill for me, basically because I don't know enough to build just to the specs, so to be safe, I'll over do it.

I'll lay the sheet horozontally on the long wall, as it's 5' long, same as a CBU sheet, and stand the sheet up on the ends, which are 3' wide, same as a sheet. That'll minimize cuts and material. I used a 5 foot level as a straight edge to make sure I installed the blocks flush with the stud wall.

I also added blocking for a grab bar and a shelf to hold shampoo & soap. (Don't like the look of a niche.) I mentioned earlier that if you cut a block a little bit long, like 1/16", and pound it in so it sticks, you'll have a MUCH easier time screwing or nailing it into place. Screwing is more accurate as there's no hammering going on, which could move the block out of position. And if you drill a pilot hole first, as you drive the screw in you'll have even less chance of shifting the block.

This block is notched to accomodate the copper pipe. You can see that the block is made of a 2x6 with a chunk of 3/4" plywood, glued and screwed to it. I did this because I was afraid the 2x6 blocking material might cup over time, (even though I bought it early and left it in the sun for 2 weeks and chose boards with a grain that tends to be stable), and the plywood would help stabilize the blocks. Crazy, I know. A contractor would never do this because he'd know it isn't necessary. But I've got the time so what the hell.

Another notched block. This pipe was only 5/8" deep inside the stud bay so I had to notch the plywood just a bit. Then I attached 2 pieces of 2x6 to it with space between for the pipe. The plywood was weakened a bit by the notch and because I cut it a little heavy, it bowed a bit when I banged it into place, maybe a 1/32". The odd coloration on the face of the block is where I planed this bow off so the block was flush with the face of the studs.

One final framing chore is to screw down the subfloor.

Tools

Table saw, circular saw, chop saw, screw guns, hammer

Activities

• Measure for blocking
• Cut 2x6 to lengths
• Rip 3/4" plywood to width and cut to length
• Assemble blocks - glue & screw 2x6 to plywood
• Install blocking with 3" drywall screws

Day 10 - Cement board 

Before the CBU goes up I needed to insulate and place nail plates to protect wiring passing through the studs. And so you don't forget where your blocking is once the tile is up, write down the locations so you can properly locate the hardware.

ICYDK about insulation: Cut it with a utility knife, paper side down, using a 2x4 or something as a straight edge. Wear a mask. Cut out for electrical boxes and if a wire passes through a stud bay, slice the insulation where the wire is and get the wire to go inside the slice.

ICYDK about nail plates: I always cut a 1/8" deep recess in the stud so the nail plate is flush with the front of the stud. Otherwise the drywall or cement board will bulge out a bit over the plates. Use a router with a straight bit set 1/8" deep or if you have just a few to do, a chisel might be quicker.

Tip: Don't go to the gym before installing cement board. AND, get the newer, lighter stuff. I made both mistakes, so I know. The first board was a full sheet to againt the 5-foot long shower wall with the edge pushed up against the ceiling. I couldn't do it. I've put up drywall by myself; even 12 foot sheets but this kicked my butt. Maybe I'm getting old.

So, using wood lying around, I made a quick little helper; a 4x4 with a 2x6 screwed to it for additional length and a piece of 1/2" plywood to create a shelf/pocket for the CBU to rest on. The bottom of edge of the CBU was to be 48" off the floor, so I made my helper about 50". (It would lean a bit when holding the CBU in place). With my helper within reach, I lifted the board into place, grabbed my helper and shoved it underneath the CBU. I kicked in the bottom of the helper to rise the sheet to it's final resting place where it held steady, allowing me to screw it down.

I suppose I could have put the first sheet down low, against the floor instead of the ceiling and use it to support any CBU installed above it, but I don't think that's how drywallers do it. They cover the ceiling first. Then, when covering the walls, they always lay the first sheet horozontally, pushed up tight to the ceiling, providing extra support for the ceiling drywall.

Even driving these 1 1/4" CBU screws was a workout. Scratch that - I started with 1 1/4" screws but they just seemed too short. Then tried both the 1 5/8" and the 2 1/4" ones and ended up using both, as well as the CBU nails. IMHO, nails are the way to go, on walls at least. I'd use both. The screws I got were difficult to get flush with the panel face; I had to push very hard on the drill and I broke a half dozen bits. And the mesh tends to tear when you do get them flush. The nails drive quicker and are easier to get flush and they leave the mesh intact. The CBU screws had little ridges on the underside of the heads, which I assume are there to cut their own countersink but it didn't work that great. I'm wondering if pre-drilling holes in the CBU would have helped. I think I'd do that next time - and it might help to pre-drill the holes if you can accurately transfer the stud locations to the CBU sheet. To clarify, if you use screws, they must be made for CBU. They make CBU nails too, but I think you can use hot dipped or electroplated galvanized roofing nails; 1 3/4". Fasteners need to be at least every 8", on all the studs and the blocking, so that's a good 25 fasteners/full sheet.

Here's another support method I used - a board screwed to the studs slightly below where the CBU would go. Using shims, I raised the CBU up to it's final position, 1/8" below the panel above it.

I cut the CBU with a circular saw and masonry blade because I had them around and didn't want to spend the 10 bucks for a CBU scoring tool. Mistake. I wore a respirator and held a vacuum next to the saw blade during the cut but I still made a mess. I cut the round holes with a cheap hole saw and the odd shaped cutout with a jigsaw and wood blade. These holes were very easy to make with these tools. (I'll toss the wood jig saw blade and we'll see how dull the hole saw is now. Like I said, I used an old cheap one.)

I taped the edges and corners with alkali-resistent mesh tape and modified thinset. Using a 6" drywall taping knife, I applied thinset to the gap and pressed it in and smothed it out. Then I stuck the tape into the thinset and embeded it by passing the knife over it while also squeezing out and removing the extra. I was afraid that I'd get too much build up of thinset which would complicate tiling but it wasn't a problem. I've read on forums about a 1/8" ridge from the taping job but I didn't get get that kind of build up at all. I suppose my lighter application of thinset might make for a weaker joint than if I'd built up a heavy ridge but since I installed good blocking, that doesn't concern me.

I'm going too use Laticrete Hydro Ban to waterproof the shower and the specs say that a substrate of exterior plywood is OK and I almost went that way until I posted the question on a forum. A tile pro named Shaughn, who answers questions on various forums out there, (this was on the Bathroom forum on garden Web), said, Plywood, even under a waterproof layer like Hydroban, is never a good substrate for tile. The wood strands in the plywood will expand and contract very differently than the mortar and tile will and that disparity will result in tension failures. The point of using a material like cement board is that it is stable against moisture and temperature changes as well as being impervious to damage caused by moisture. Well written. Made sense to me.

Tools

Circular saw with masonry blade, Jig saw, hole saws, mortar mixing paddle, 1/2" corded drill for the paddle

Day 11 - Curb, Kerdi Drain 

Before I forgot I screwed the 1/2" plywood down to the 2x6 T&G. I re-measured for and marked the curb and drain locations. BTW, the drain hole cutout is 4 1/2" and I can verify that a 10 lb cat can fit through a hole this size. The cup hole on a golf green is 4 1/4". Curiosity...

The Kedri Drain kit comes with styrofoam spacers to hold the drain flange up from the floor 3/4", which may be high enough for a cement floor but for wood you need to go more like 1 1/2"; Schluter instructions say at least 1" for a wood floor. So I set the foam blocks on bits of 3/4" plywood to bring it up to 1 1/2". The pan should have a slope of at least 1/4" per foot so I measured from the drain flange to the floor, 1 1/2", and the distance to the farthest wall, 2'. 2' x 1/4" = 1/2". 1 1/2" + 1/2" = 2", would be my pan perimeter height. The black Sharpie lines along the bottom of the walls are my reference lines for where the pan will be built.

I've also read that the drain flange is sloped at 1/4" per foot so I tried to place a straight edge on it, carrying the slope to the wall and came up with a perimeter height of 2 3/4", too much. This exercise is shown in the photo; waste of time. BTW, 1/4" per foot is the minimum floor slope by code and 1/2" per foot is the max.

The Kerdi drain is adjustable up and down from 1/4" TO 1-1/4" and laterally about 1/2" in all directions. The parts that move are the black plastic bits attached to the metal grate, shown in the photo. More on this later when it's time to tile but basically, the one piece is a cylinder which moves up and down and is also smaller than the drain in which it sits so you can slide it around.

Curb dimensions are up to you, though the top of the curb must be 2" higher than the drain, per building codes. Curbs are often a weak point in terms of waterproofing so it's best to use as water-resistent material as possible to build them. 2x4's are commonly used, but they're not very water resistent. Exterior grade plywood is better and even better would be mortar or a stack of CBU, all screwed together. You could use glue too - look for a masonry glue of some kind. The top of the curb should be sloped into the shower, say about 5 degrees to shed water. With a CBU stack, you could get your top bevel with some thinset on top, before you add waterproofing.

I built my curb from a sandwich of exterior plywood pieces with a 5 degree slope on the top. Once installed, I encased it in CBU. I've read you should't put CBU directly over 2x4's but I know it's done all the time. I like a narrow curb and not too high but I had to keep to code which is 2" above drain level. Since my shower pan will be 1 1/2" thick at the drain flange, per the flange installation instructions, and tile and thinset will add another, say, 1/2" to the drain height, my curb would need to be at least 4" high. I don't know of any code governing curb width, but it needs to be wide enough to be stable; it's hard to attach something too thin firmly to the floor. So, I ripped a 3/4" exterior grade plywood sheet into 3, 5' long, 4 1/2" wide strips. Glued and screwed them all together. Then I ran that assembly through my table saw with the blade set at 5 degrees, to put a slope on the top surface. The final dimensions of this wood assembly was 4 1/2" high, 2 1/4" wide and 5 feet long. The top of it had the 5 degree bevel, with the low side facing into the shower. I figured any thinner, say I'd used just 2 3/4" strips, it would have been too tippy, even if well attached to the floor. I drilled countersink holes into the curb and used 3" screws to attach it to the floor. I also angled some screws in the sides, down into the floor, like toenailing; these were countersunk a bit too, just to get the screw heads below the surface.

Then I cut strips of CBU to cover it, adding 1/2" to top and sides, resulting in a curb 5" high and 3 1/4" wide. It'll grow even more when I tile it; so my once minumal curb is turning out to be fairly clunky. I cut the CBU strips with a 5 degree bevel where appropriate. What I plan to do is tile the sides of the curb and make a concrete top for it that overhangs the sides just about 1/4" or 1/2". This will be another project in itself; my first foray into the concrete countertop world. I'm doing the vanity top with concrete too. To avoid a clunky curb, next time I'll experiment with attaching a thinner curb to the floor; see if I think it's stable enough.

I put a piece of roofing felt down for a slip sheet, (decoupling membrane), and stapled a sheet of metal mesh in preparation of starting the mud pan. That'll be Friday - day off tomorrow. Heading into the city for a long walk and meet a bunch of friends at the Page Bar, allows dogs. Didn't do too much today - cleaned the garage & house, regrouped.

Day 12 - Mud Pan 

I bought John Bridge's book, "Tile Your World", which shows how to use a Kerdi Drain with a mud pan and he's got a good how-to on how to mix deck mud at the John Bridge forum's: http://www.johnbridge.com/how-to/deck-mud/. Doing a mud pan isn't that difficult but I was covered in sweat when done, probably due to stress as much as heat. Now that it's done, I worried for nothing; it's not that difficult.

Some people like to use latex admixture or something like it to increase strength and hardness but I've read that this isn't necessary and makes the mud job more difficult, not to mention cleanup. The modified mud will stick to your trowel and set up sooner and harder, making it more difficult to work. John Bridge recommends just a mix of sand and cement, in about a 5:1 ratio. I bought my mud already mixed in a 5:1 ratio from a tile supply shop for $5 per 60lb bag. That said, I've also read a post by a pro who says it's easier for him to use a fortified mud but that may be because he's a pro and doesn't need to work the mud for long - he gets it right the first time. Also, if you're using Laticrete's Hydro Ban like I am, you nullify the 25 year warranty if you don't use Laticrete's brand of fortifed deck mud. I didn't know this at the the time so if I did this again, I'd probably use the fortified mud. But the world of warranties is murky, IMHO; they may demand overkill as a CYA measure and serve a promotional role for the company's own products. But if that warranty is important to you, you must use what they say and document everything. I think the 3000 psi of the sand and cement mix will be strong enough; Laticrete's fortified mud is about twice that. Like I say though, I'd probably try the fortified - but if you do and you've never done a mud pan, I'd suggest doing a dry run first. Make a box with a plywood bottom and 2x4 edges inside of which you'll form your practice pan. Just a thought.

This photo shows the drain set into some loosened mortar, (a little more water added to it so it's not so dry). I used a bit less than a half of a 60 lb bag of mud for this step, piling it up around the edge of the drain hole in the floor. I set the drain to height by pushing down on it, twisting it some, to 1 1/2" off the floor while keeping level at the same time. Something I didn't do but I think is a good idea is to mix up a little latex modified thinset and spread it on the bottom surfaces of the drain and maybe even the floor around the drain before piling the deck mud around the drain. Some people have reported that the drain may be a little loose the next day after the pan dries a bit and the thinset will help bond the drain and mud. I forgot to do this but my drain is solid in the pan as I write now, two days after I did the pan. I pulled as hard as I could and couldn't budge it. However, when I tap around on the flange, there are two small spots that give a plastic-y sound, indicating there's no support right beneath. The gap must be just a tiny fraction of an inch. But 95% is absolutely solid so I'm going with it. What I did do while setting the drain though is to lift the drain and check to see the coverage of mud beneath it; see if it was fully supported with no voids in the mud. It was. There was a perfect impression of the drain in the mud when I checked. Maybe I should have left it alone as this may be how the 2 voids were created. Also, I thinke I should have made the mud even looser. Actually what I should have done is put thinset on the flange before setting it. Like I say, I'm going with it - should be fine. Google "Youtube kerdi-drain" and you'll get a video I'm sure. Everybody wants to be a star.

After the drain was set, I went back outside and mixed 1 1/2 bags in a wheelbarrow and carried it inside in two trips using a 5-gallon bucket. I spread the mud around the perimeter and packed it down along the perimeter, leveling it to the reference lines I'd made earlier.

So now I had the level set by the drain in the middle and the level at the perimeter set by the build up of mud at my level line on the wall, leaving me to fill in between. Back outside to mix more mud and haul it in. I filled in the middle, packing it down as I went. Before starting I'd cut a series of 1x2's to different lengths, from 1 to 2 feet, to use as screeds. You put one end on the drain flange and the other on the perimeter and the board will define the level of the mud in between. It's best to use straight, clean and sharp edged wood for your screeds. One more tip: Use good lighting, especially if you're getting into the presbyopia years; readers alone sometimes don't cut it in insufficient light.

I didn't stop to photograph during the mud job but here's the finished product. You have to keep moving but there's no reason to stress too much. If you don't add latex, you'll have time to work the mud and even have calm moments after cleaning up to go back and caress your new pan with a nice clean trowel.

Here's a close up of the drain and the mud surface after I was done. I spritzed it with water and covered it with a couple of trash bags to prevent it from drying out too soon. I don't think the pros do this, as they need to move; tile the next day. But I'm able to wait a couple days before tiling; play some golf. Actually, I'm using Hydro Ban to waterproof the shower and I HAVE to wait 72 hours before applying it.

Day 16 - HydroBan 

Some skipped days here as I had to let the mud pan cure for at least 72 hours. Hydro Ban coverage is 50 sq. feet per gallon and I had 100 square feet; 2 gallon buckets should do it. This stuff is the consistency of mayo; maybe a little less stiff. I stirred it only because the list of tools needed includes a mixing stick. I'm not sure it needed mixing; seemed mixed already.

Following the instructions, I cleaned all surfaces with a wet sponge and vacuumed everything; sanded the copper pipe. Then I drew some lines on the walls and pan with a Sharpie to better determine whether I have proper coverage; you shouldn't be able to see the black lines after two coats. In this photo you can still clearly see, after one coat, a miss-mark I made when locating holes to cut in the CBU. I put the first coat on and found that pushing the stuff into the little square holes of the CBU, created by the mesh on the surface, by not just rolling the roller but smearing it around in all directions, even sideways. Then I'd roll normally to smooth out any ridges from the smearing technique. You can still the CBU texture after the first coat. If I did it again, I'd try to get it on thicker during the first coat.

I didn't use the Laticrete mesh on the corners or around the drain but some people do. Laticrete says it's not necessary. I did however tape all the CBU corners with mesh tape and thinset before the Hydro Ban application. I've read where people will skip the CBU taping and then they tape the Hydro Ban, using Laticrete's fabric, to make up for it. If you follow all manufacturer's instuctions, you'll do what I did, tape the CBU but not the Hydro Ban. Some people like overkill and tape both. Also, I've read where people will put a third coat on built-in seat and niches, just for added confidence.

Also, you don't really need to coat the shower walls above the level of the shower head because very little water will reach that high but I did it anyway. If your square footage is about equal to an even number of Hydro Ban pails, like mine was, you might leave this area alone and if you have extra after the second coat, then do it. But as a DIY'er who has money and time for overkill, why not just do it.

Here's the Kerdi drain after applying the Hydro Ban. I applied the Hydro Ban over the textured part of the drain flange, the ghost of which is visible. I suppose you could stop anywhere between the depression that serves as the cradle for the drain assembly and the holes around the outside edge of the flange - it's all solid plastic afterall. You don't want to slop it into the depression/cradle as the drain assembly needs to slide around in the depression for adjustment to the tile layout. I got a little in there but it wasn't a problem.

It took a good two hours for it to dry to the touch but I waited overnight for the next coat. The stuff dries to an olive green color but it's really the same color as when wet; it just darkens a bit when dry. The instructions say it needs to dry to a uniform olive color but I think I saw somewhere that you need to let it cure between coats, whatever that means. The formulation has changed since it first came out and I think it dries faster now. I can still see most of the sharpie lines and I used almost one full gallon container. When dry, it doesn't feel like rubber at all, like I expected. It just feels dry, like a surface painted with a flat paint.

It's the next day and the Hydro Ban is fully cured and now I can see ALL the sharpie lines. I put on the second coat and laid it on heavier this time but still only used about 3/5 of a gallon, so the CBU really soaked up the first coat. Since I have some left over, tomorrow I'll go over the corners, fix any light spots or pin holes I see. Most of the Sharpie lines are hidden now and I don't think I'll need to buy a third gallon.

This photo is taken soon after I put on the second coat. You can still see a hint of the Sharpie mark. When you roll this stuff on, don't roll it out much. Unlike painting, I left it thick enough so the roller texture was visible. You can see the different textures in the photo; the square mesh vs. the roller texture, which is still a little wet. I also figured aout that since I wanted good coverage in the corners, if I loaded up a paintbrush and used it like a trowel almost, like one of those inside corner trowels you can get for drywall mudding, then clean up the ridges you leave behind. Not that I loaded the corners real thick; I just wanted to get them well covered. Also, if you use a brush with longer bristles, you'll be able to leave more material behind. I bought cheap brushes and rollers, 3/8" nap, and tossed it all after each application. Use pan liners too. This stuff does clean up with water but I'm lazy. Use something like a shim to scrape the roller and push out what's loaded inside - you'll get a good half pint out of it. They make roller scrapers for this, with a half circle shape that conforms to the roller. Use the brush then to apply it where you think the coverage is lighter.

Now it's Thursday, Aug. 4, (512 drop in the DOW), and I can only faintly see bits of a couple of the sharpie lines. I applied the rest of the second gallon to the corners, floor and lower walls. In some places there were still tiny holes, where the material seeped into a CBU mesh hole, though I'm pretty sure the hole doesn't go all the way to the CBU; there's some hydro ban in there. But still, using a brush I filled/repaired all these pin holes. Like I mentioned, the most surprising thing about this stuff is that it's not at all like a rubber coating after it dries; it just feels dry, neither slippery nor thick. Feels more like flat paint.

I'll post in a couple of days when I start tiling the shower. That'll be a new page.

Add your comment:

Url (required)

Name (optional)

E-Mail (optional)

Your Comment

What's 5 and 2 : (To make sure you're human; not a spammer program.)

Add Comment